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Aging Is Associated with Endothelial Dysfunction in the Human Forearm Vasculature
Author(s) -
MD Nabil Andrawis,
MD Drew S. Jones,
MD Darrell R. Abernethy
Publication year - 2000
Publication title -
journal of the american geriatrics society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.992
H-Index - 232
eISSN - 1532-5415
pISSN - 0002-8614
DOI - 10.1111/j.1532-5415.2000.tb03911.x
Subject(s) - medicine , acetylcholine , sodium nitroprusside , forearm , brachial artery , vasodilation , plethysmograph , vascular resistance , endocrinology , angiotensin ii , ec50 , endothelial dysfunction , endothelium , ageing , nitric oxide , blood pressure , anatomy , biochemistry , chemistry , in vitro
OBJECTIVE: Our objective was to examine the role of the endothelium in maintaining vascular tone in the basal as well as in the contracted state during aging. DESIGN/PARTICIPANTS: Responses to brachial artery infusion of acetylcholine in presence and absence of N G ‐nitro‐L‐arginine methyl ester (L‐NAME) and to angiotensin II were studied in 11 young and 12 old white subjects. MEASUREMENTS: Strain gauge plethysmography was used to measure forearm vascular resistance (FVR). The dose of acetylcholine at 50% maximal observed decrease in forearm vascular resistance (EC 50 ) was significantly higher (11.0 ± 1.59 vs 7.07 ± .65 μg/min, respectively; mean ± SEM; P < .05) and the FVR at maximal acetylcholine effect (Emax) remained greater (12.6 ± 1.75 vs 7.15 ± 1.25 mm Hg/100 mL tissue volume/min; P < .02) in old compared with young subjects. Acetylcholine effect was significantly reversed by concomitant administration of L‐NAME, as indicated by the increase in EC 50 (old, 20.2 ± 3.69; young, 11.9 ± 1.68 μg/min). RESULTS: There was no age‐related difference in sodium nitroprusside‐induced decrease in FVR. The EC 50 and Emax for angiotensin II‐mediated increase in FVR were 7.87 ± 1.15 and 8.36 ± 1.00 ng/min (EC 50 ) and 5.30 ± .67 vs 6.56 ± 1.25 mm Hg/100 mL tissue volume/min (Emax), and these were not different in old and young subjects, respectively. CONCLUSIONS: These data indicate that aging is associated with impaired endothelial‐ dependent vascular relaxation and that this is selective, with no age‐related change in endothelial‐independent vascular relaxation or angiotensin II‐mediated vascular contraction. J Am Geriatr Soc 48: 193–198, 2000.